Absolute encoder and method for generating an absolute value for a angle of rotation

US8324892B2 · kind B2 · utility

Assignee

• ebm-papst St. Georgen GmbH & Co. KG · DE

Inventors

• Christian Rudel · Speicher, DE
• Jörg Hornberger · Dornstetten, DE
• Michael Schäuble · Lambach, DE
• Michael Kisch · St. Georgen, DE

Key dates

• Filing date: Jul 19, 2006
• Grant date: Dec 4, 2012
• Expiry date: Nov 11, 2027

Classification

• Technology area (CPC G): Physics
• CPC primary: G01D5/2455
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An electric motor (10) has: a stator (12) and a rotor (14) having a shaft (87). The rotor (14) has a sensor magnet (82) having a number SP of sensor poles (71, 72, 73, 74) for generating a predetermined distribution of the magnetic flux density, such that SP=2, 4, 6, 8, etc. The motor also has at least two rotor position sensors (450, 455, 460, 465) for generating rotor position signals (B_S1, B_S2) characterizing the magnetic flux density, the rotor position sensors (450, 455, 460, 465) being arranged in the region (30) of the circumference of the sensor magnet (82). The motor also has an evaluation apparatus (32) that ascertains, from the rotor position signals (B_S1, B_S2), an absolute value (phi_el, phi_mech) for the rotational position of the rotor (14). A method of generating an absolute value for the rotational position of an electric motor is likewise described.